Though along the coast we’ve not had any truly cold temperatures yet this winter, it is time to bring your houseplants indoors until spring. But how is the best way to do this, to minimize stress for the plants and to avoid introducing pests into your home environment?

Before bringing plants inside, inspect them carefully for insects, and hose them off thoroughly to clean off any pests and dust. If necessary, treat with an organic insecticide, such as a soap spray. Allow plants to dry in a protected place and then move them indoors. Inspect them frequently throughout the winter to catch any infestations before they become major problems.

Many houseplants originate in the tropics so grow best where they are surrounded by warm air that is very humid. Though our outside air may be quite moist, when we turn on our furnaces or heaters, the humidity inside will drop drastically; this is true even if a whole house humidifier is attached to the furnace. Some plants will adapt to the sudden change in conditions without much fuss, but some, such as Ficus benjamina, will react drastically by doing something scary like suddenly drop all their leaves. Others may decline slowly (and to the owner, painfully), with lessened vigor, yellowed foliage, or begin to look “off.” How to cope? Avoid placing plants directly in the air draft from a furnace vent. Increase the humidity around your plants. One easy solution is to place them on large saucers filled with water, so that the air surrounding them stays moist as the water evaporates. Since roots will rot if kept constantly wet, the pot bottoms must be elevated above the water; you can use commercially made pot “feet” or a layer of pebbles or marbles in the saucer. You can also invert a second saucer or shallow pot in a larger one, to become a pedestal on which a pot rests. Use your imagination to come up with attractive or unusual ways to raise your containers above the water-filled saucers. Those who heat with wood often place a water-filled kettle on the stove so that moisture is given off as the water in the kettle heats. Others cluster their plants in a bathroom or kitchen where water from daily living tends to raise the humidity in the surrounding areas. A small indoor fountain can offer not only increased humidity but also the soothing sound of moving water, and can look right at home surrounded by plants. Except for those with hairy leaves, such as African violets, most plants also benefit from being misted occasionally with a very fine spray.

Declining plant health can also be caused by the sudden change in light levels from outdoors to indoors. Many houseplants are understory natives in their original habitats. Though they like shady conditions, they require a certain light level to photosynthesize and remain healthy and vigorous so most will need to spend the winter by a window or under artificial light. (Dark corners and dim room interiors provide adequate light for only a very few species. (Go here for a list of low-light tolerant plants: www.annsentitledlife.com/how-does-your-garden-grow/10-best-low-light-houseplants/.) Most gardening books and the internet will give you some guidelines on light needs of specific plants but watch your plants because they will give you notice: if the foliage looks yellowed or dull, and especially if they seem to be getting leggier, or stretching out abnormally, they may need stronger light than they are getting.

On a chilly damp winter day, when we are stuck indoors, few things brighten up our gardening spirits more than a few healthy happy houseplants. It is well known that indoor plants clean the air as they take in carbon dioxide and give off oxygen but for most of us, it is the sense of living in a green and growing environment that makes us enthusiastic indoor as well as outdoor gardeners. And don’t forget that you can brighten others’ spirits by giving a flowering house plant as a holiday gift. Poinsettias are usually appreciated but perhaps even more welcome would be one of the longer lasting flowering species, such as gloxinias or peace lilies. For a list of easy-to-grow flowering house plants, go here: balconygardenweb.com/17-best-flowering-houseplants/.

Garden tips are provided courtesy of horticulturist Sharon Hull of the San Lorenzo Garden Center. Contact her at 831-423-0223.